69 research outputs found

    Materiales y tecnologías en la Arquitectura Modernista: casos de estudio de decoración de fachadas en Italia, Portugal y Polonia persiguiendo una restauración racional

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    The results of a diagnostic survey on the materials of representative Art Nouveau buildings in Italy, Portugal and Poland are here presented and compared, as a contribution to their understanding and, hence, to support compatible restoration. In particular, the facade decorations were investigated for the appraisal of their materials and technologies, often neglected in current maintenance/restoration works and so cancelled, leading to a severe loss in architectural image. The ongoing diagnostic campaign, in collaboration among different universities, is aimed to set up a database on materials and technologies of Art Nouveau facade decorations at a European scale, as a technical-scientific background for the highlighting of preservation guidelines

    Graphene Oxide: An All-in-One Processing Additive for 3D Printing

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    Many 3D printing technologies are based on the development of inks and pastes to build objects through droplet or filament deposition (the latter also known as continuous extrusion, robocasting, or direct ink writing). Controlling and tuning rheological behavior is key for successful manufacturing using these techniques. Different formulations have been proposed, but the search continues for approaches that are clean, flexible, robust and that can be adapted to a wide range of materials. Here, we show how graphene oxide (GO) enables the formulation of water-based pastes to print a wide variety of materials (polymers, ceramics, and steel) using robocasting. This work combines flow and oscillatory rheology to provide further insights into the rheological behavior of suspensions combining GO with other materials. Graphene oxide can be used to manipulate the viscoelastic response, enabling the formulation of pastes with excellent printing behavior that combine shear thinning flow and a fast recovery of their elastic properties. These inks do not contain other additives, only GO and the material of interest. As a proof of concept, we demonstrate the 3D printing of additive-free graphene oxide structures as well as polymers, ceramics, and steel. Due to its amphiphilic nature and 2D structure, graphene oxide plays multiple roles, behaving as a dispersant, viscosifier, and binder. It stabilizes suspensions of different powders, modifies the flow and viscoelasticity of materials with different chemistries, particle sizes and shapes, and binds the particles together, providing green strength for manual handling. This approach enables printing complex 3D ceramic structures using robocasting with similar properties to alternative formulations, thus demonstrating the potential of using 2D colloids in materials manufacturing

    Micromechanical strength of individual Al2O3 platelets

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    Optimising the properties of platelet reinforced composites requires the strength of the reinforcing phase to be known, however strength measurements at such small scales are difficult and therefore data is sparse. In this work the flexural strength and Weibull modulus of microscopic, alumina platelets has been measured as 5.3 ± 1.3 GPa and 3.7 respectively, using an in-situ micro 3-point bend test. A general approach to correct for the effect of variation in sample size on the Weibull modulus is presented, and the internal structure of the platelets is revealed by TEM

    Malaria prevention in north-eastern Tanzania: patterns of expenditure and determinants of demand at the household level

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    OBJECTIVE: This study aims to provide a better understanding of the amounts spent on different malaria prevention products and the determinants of these expenditures. METHODS: 1,601 households were interviewed about their expenditure on malaria mosquito nets in the past five years, net re-treatments in the past six months and other expenditures prevention in the past two weeks. Simple random sampling was used to select villages and streets while convenience sampling was used to select households. Expenditure was compared across bed nets, aerosols, coils, indoor spraying, using smoke, drinking herbs and cleaning outside environment. FINDINGS: 68% of households owned at least one bed net and 27% had treated their nets in the past six months. 29% were unable to afford a net. Every fortnight, households spent an average of US 0.18onnetsandtheirtreatment,constitutingabout470.18 on nets and their treatment, constituting about 47% of total prevention expenditure. Sprays, repellents and coils made up 50% of total fortnightly expenditure (US0.21). Factors positively related to expenditure were household wealth, years of education of household head, household head being married and rainy season. Poor quality roads and living in a rural area had a negative impact on expenditure. CONCLUSION: Expenditure on bed nets and on alternative malaria prevention products was comparable. Poor households living in rural areas spend significantly less on all forms of malaria prevention compared to their richer counterparts. Breaking the cycle between malaria and poverty is one of the biggest challenges facing malaria control programmes in Africa

    Imitation and intangibility: postmodern perspectives on restoration and authenticity at the Hill House Box, Scotland

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    Restoration is often problematised within built heritage practice as an inauthentic activity of imitation. This is symptomatic of a Western focus on physical heritage sites, which is underpinned by an amalgam of scientific materialism and visual aesthetics. Situated within a postmodern conceptualisation of heritage as increasingly dynamic, social and intangible, this study suggests the relationship between restoration and authenticity is increasingly out of step with contemporary perspectives and would benefit from a critical gaze. Drawing on Baudrillard’s theory of ‘hyperreality’, this study makes space for two key concepts within the built heritage paradigm: authenticity as emergent and fluid; and the legitimisation of imitation as a valid activity. Together, these are explored in relation to the restoration of the Hill House, Scotland, and its encapsulation within the ‘Hill House Box’. From a postmodern, Baudrillardian outlook, the site becomes a dynamic performance between the restored building (a tangible ‘simulation’ of an idealised essence) and the users of the Hill House Box (an intangible, ritualised experience). Consequently, this demonstrates how the amalgamation of imitation and intangibility can overcome binary views of original/copy; authentic/inauthentic, resulting in the creation of emergent authenticity and aura that the Box both creates and is engulfed within

    Data for: High Temperature Strength of an Ultra High Temperature Ceramic produced by Additive Manufacturing

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    HfB2 paste rheology and mechanical properties
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